The subject matter of this invention is described in Disclosure Document No. 120357 filed Sept. 6, 1983.
This invention relates in general to holders for cut photographic film. More specifically, it is directed to a new disposable package for cut photographic film, and an improved holder for use therewith.
In the field of professional photography, the use of relatively large format cut photographic film is preferred for many applications. This type of film is conventionally preloaded in the dark room into rectangular film "holders," each of which accommodates two sheets of cut film. Such film holders are subsequently inserted into an aperture in the back of the camera for exposure, withdrawn and return to the dark room for unloading and developing. An example of this type of holder is sold by Lisco Manufacturing Co. under the trade name "LISCO REGAL."
In order to have an adequate supply of film, it is necessary for the photographer to preload a large number of such film holders, to transport them to the location where they are being used, and to transport them back to the dark room for unloading and processing. Such an arrangement has a number of disadvantages. Primary among these are the relative bulk and weight of the holders themselves, each loaded holder weighing about 7 ounces, the time required to preload the holders, the potential for incorrect loading, and the risk of contamination and finger prints. Temperature and oxidation control of the unused portion of the film stock contained in the opened bulk pack in which the supply of cut film is purchased are also a problem. Once the air tight manufacturer's seal is broken to remove only a few sheets of color film from a bulk pack, the remainder cannot be returned to cold storage, as is generally required with professional photographic film, because of moisture condensation risk; and because the package is no longer airtight, the film begins to oxidize. Thus, if the film in a broken pack is not used promptly, it is usually discarded to avoid the risk of spoilage and loss of work product.
A number of attempts have been made in the past to remedy these problems by providing a disposable film package which can be loaded into a film holder in daylight at the point of use, and withdrawn after the film has been exposed. In this manner, a single holder can be reused, eliminating both the need to transport large numbers of film holders on location, and the requirement for dark room preloading and unloading of film by the photographer.
Typically such disposable film packages consist of a substantially flat film carrier to which two sheets of cut film are attached, one on each side of the carrier. The carrier is packaged in an envelope having one open end through which the carrier may be withdrawn for exposure. In use, the film package is to be inserted into the holder, open end first so that the sheets of film are properly positioned in the holder for exposure in a camera. Once the package is fully inserted into the holder, means are provided for locking the carrier in position so that the envelope may be withdrawn leaving the sheets of film ready to be exposed. After exposure, the envelope is to be reinserted into the holder, over the film carrier. The carrier is then unlocked so that the package, with the carrier once again contained in the envelope, may be removed, turned over and reinserted to expose the second sheet of film.
Two examples of such disposable film packages are disclosed in U.S. Pat. Nos. 689,271 to Ashford et al. and 1,505,000 to Whiting. One of the principal difficulties encountered in all such prior art film packages centers around the necessity of providing and maintaining a light tight seal at the open end of the envelope at all times when the package is outside of the holder. The Ashford et al. patent attempts to provide such a seal by means of an enlargement at one end of the carrier having a recess into which the edges of the open end of the envelope may be inserted. The principal disadvantage of the Ashford et al. arrangement is that the light tight seal is particularly apt to be breached by incomplete or incorrect reinsertion of the envelope after its withdrawal for exposure of the film, by improper seating of the open end of the envelope due to incorrect alignment with the recess upon reinsertion, or by separation of the open end of the envelope from the recess due to jostling upon withdrawal. This difficulty is compounded by the fact that both the Ashford et al. and Whiting inventions anticipate that the envelope will be completely withdrawn from the carrier, thereby causing a certain amount of jiggling of the carrier as the operator attempts to align the envelope for reinsertion.
This shortcoming was less important at the time when the Ashford et al. and Whiting packages were conceived because the relatively slow speed of film then in use allowed the photographer adequate opportunity to correct any break in the light seal due to incorrect or improper seating of the envelope. With modern high speed photographic film, however, any light leakage, however small, is likely to ruin a piece of film in only a tiny fraction of a second.
Accordingly, it is a principal object of the present invention to provide a disposable film package having a highly dependable means for establishing and maintaining a light tight seal at the open end of the package's outer envelope.
Another object of this invention is to provide a disposable film package which may be withdrawn from the film holder in such a manner as to prevent accidental breach of the light tight seal.
Another object of this invention is to provide a disposable film package with means to assure withdrawal of the external envelope only as far as is necessary to allow complete exposure of the film.
Still another object of this invention is to provide a disposable film package having means to provide for the correct alignment of the envelope and the carrier upon reinsertion of the envelope into the holder, thereby assuring correct and complete sealing of the open end of the envelope.
Yet another object of this invention is to provide a new film holder for use with the disposable film package, which is simple, lightweight, economical in construction and convenient to use.
Another object of this invention is to provide a new film holder for use with the disposable film package having improved means for retaining the carrier in the holder when the film is withdrawn.
These and other objects of the invention will be more fully understood from the following detailed description of the preferred embodiments which should be read in light of the accompanying drawings.